Wood-pulp grinder.



H. E. TIDMARSH.

WOOD PULP GRINDER. APPLICATIQN FILED :uu/1o, 191s.

Patented July 3, 19W..

3 SHEETS-SHEET 2.

HyE. HDMARSH@ WOUD PULP GRINUEB.

APPLICATION FILED JULY l0. 1916.

Lhmg Patented my 3, 1917.

3 SHEETS-SHEET 3.

un? run sanare raras' ermee.

HARRY E. TIDMARSH, OF BANGOR,` MAINE, ASSIGNOR 0F ONE-HALF TO UNION IRON WORKS, OF BANGOR, MAINE, .A CORPORATION OF MAINE.

WOOD-PULP GRINDER.

Specification of Letters Patent.

Patented July 3, 1217.

Application fried July 1o, 191e. serieu No. 108,321.

To all whom t mag/concern:

Be it known that I, HARRY E. TIDMARSH., a citizen of the United States, residing at Bangor, county of Penobscot, and State of Maine, have invented certain new and useful Improvements in l/Vood-Pulp Grinders; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same. p i i rThis invention relates to wood pulp grinders and has for its object to provide a grinder construction in which the grinding is accomplished with less expenditure of power than heretofore without diminishing the quantity or quality of the output.

In wood pulp grinders as now constructed, material to be ground is placed in pockets arranged radially of the circumference of a stone on a horizontal shaft, the pockets being usually above the axis of rotation of the stone so that the pressure upon the material in the pockets produces a heavy, unbalanced lateral thrust on the shaft, the total thrust resulting from the weight of the stone and the pressure on the material amounting in some cases to more than thirty tons between a single pair of bearings.

I have found that a large per cent. of the power heretofore necessary to drive the shaft of the grinder has been consumed in the friction of the bearings resulting from this unbalanced thrust, it being practically impossible to provide a shaft strong enough to support a load of this character between bearings necessarily widely separated without deflection from the exact axial line of the bearings.

By my invention I provide a shaft bearing and a supporting construction therefor which permits a deflection of the shaft at the bearing without increasing the frictional load at the bearings, and I have found by actual operation that the operating power may be reduced by as much as 25% of the power heretofore necessary without reducing the quantity of the output or the pressure of the material against the stone.

In the accompanying drawings I have illustrated a wood pulp grinder constructed in accordance with my invention, and in said drawings,

Figure 1 is an end elevation of a pulp grinder constructed in accordance with my invention; F ig. 2 is a vertical sectional view of the grinder shown 1n Fig. 1; Fig. 3 is a vertical sectional yview through the shaft bearing at the right of Fig. 2; Fig. t is a detail view of a portion of the bearing support, and Fig. 5 is an inverted plan view of the base of the bearing support.

Referring to the drawings, 1 indicates the frame of the machine consisting of two spaced side walls to receive the stone 2 between them and supporting around the upper half of the stone the pockets 3 in which the material to be ground is placed.

The pockets extend radially of the stone, as shown, and each pocket is provided with a pressure plunger et closing its outer end, the plunger being attached to the innerl end of a piston 5 working in the pressure cylinder 6 forming a radial extension of each pocket.y As shown, the pockets are three in number, but it will be understood that a` greater or less number may be provided, as desired. Each pocket is provided with a suitable valve 7 through which the fluid under pressure may be admitted through either end of the cylinder to force the plunger against the material or lift the plunger out of the pocket when the pocket is to be charged.

Eachpocket has one side wall formed of a sliding gate through which material to be ground is placed in the pocket when the plunger is raised.

The stone 2 is supported on a shaft 8 extending across the space between the frame walls 1 and is clamped in place between the flanges 9 threaded on the shaft, as shown in Fig. 2. The ends of the shaft 8 project beyond the frame walls 1 and are supported in bearings 9a of identical construction, one of which is shown in detail in the drawings and will now be described. Each bearing comprises a supporting yoke `10 bolted to the extending base plates of the frame 1 and an external bearing ring 11 supported by the base of the yoke immediately below the center line of the bearing by a ball joint 12, as shown in Figs. 3 and 5, the ring being centered between the arms of the bearing yoke by suitable adjusting screws 13.

'Ihe bearing ring is mounted to be vertically adjustable in the yoke, the adjustment being elfected by a rotating cam 141- which constitutes the lower half of the ball joint 12, the cam 14: resting on the coperatng stationary cam piece 15 fixed in the base of the yoke. The cam 111 is centered in the base of the yoke by means of an upwardly projecting flange 16 surrounding its spherical bearing surface, the flange having a rotating lit in the transverse web of the face of the yoke. The cam piece 14: is adjusted by means of a rack nut 17 threaded on a screw 18 extending across the base of the yoke, the teeth of the rack meshing with corresponding teeth formed in a tongue 19v projecting from the side of the cam.

The bearing ring 11 houses the exterior race 20 of a ball bearing, the race being clamped within the ring 11 by means of the side flange rings 21 bolted to the opposite edges of the ring 11.

The inner race 23 of the ball bearing is carried by a sleeve 22 keyed to the shaft 8. The race 23 is clamped to the sleeve 22 by means of a clamping ring 24 threaded on the sleeve and clamping the race against a flange formed on the sleeve on the opposite side of the bearing.

Between the two races there is provided a double row of bearing balls,y each row of balls having their separate groove in the inner race whereas the bearing face of the outer race is ground to a spherical curve.

The bearing is lubricated through oil or grease ducts 25 formed in the rings 11 and 21 as shown at the `bottom of Fig. 3. The loss of lubricant between the two parts of the bearing is prevented by means of packing rings 26 bolted to the faces of the rings 21 and provided with spaces for packing indicated at 27. Each of the packing rings is formed with a pair of inner circumferential grooves beyond the groove for the packing ring to which grease may be fed, as indicated.

In operation the heavy load or unbalanced thrust on the shaft deflects the center of the shaft from its normal axis of rotation, the effect being to tilt the bearing rings toward each other` at the top. This action is permitted by the ballV joint 12, the centering screws' 13 working in grooves of suflicient amplitude to permit this slight movement.

The two parts of the ball 'bearing are also capable of independent angular movement by reason of the spherical bearing face of the outer race, the angular movement permitted by the ball bearing producing with the angular movement of the bearing rings a universal mounting for each end of the shaft so that the stresses produced by both the angular deviation of 'the shaft and the drawing together of the ends of the shaft kcan be wheel, pockets for the material to be ground surrounding said wheel and arranged to exert an unbalanced lateral thrust on said shaft, means for supporting said shaft comprising a ball bearing for the shaft, a carrier for the outer member of the ball bearing, said carrier having a supporting pedestal, a pivotal oint supporting said pedestal and a fixed yoke having its arms engaging the sides of said carrier and limiting the movement of said pedestal on its joint.

2. In a pulp grinder, the combination of a grinding wheel, a. shaft supporting said wheel, pockets for the material to be ground surrounding said wheel and arranged to exert an unbalanced lateral thrust on said shaft, and means for supporting said shaft comprising aV ball bearing for the shaft, a carrier for the ball bearing mounted for angular movement in the plane of the axis of the shaft and direction of the unbalanced thrust produced by the pressure on the material in the pockets, said ball bearing having the wearing face of its outer race ground to a curve to permit relative angular movement of the two races of the bearing without cramping the bearing balls.

3.' In a pulp grinder, the combination of a grinding wheel, a shaft supporting said wheel, pockets for the material to be ground surrounding said wheel and arranged to exert an imbalanced lateral thrust on said shaft, means for Vsupporting said shaft comprising a ball bearing ifor the shaft, a carrier for the outer member of the ball bearing, said carrier having a supporting pedestal, a pivotal joint supporting said pedestal and arixed yoke having its arms engaging the sides of said carrier and limiting the movement of said pedestal on its joint, and means for vertically adjusting said carrier in its yoke. Y

In testimony whereof I aflix my signature.

HARRY E. TIDMARSH.

Copies of this patent 'may be obtained for ve cents each, by addressing the Commissioner of Patents,

v Washington, D. C. 

